Change --hide-package-warnings to --show-package-warnings and add hint on suppress warnings.

sdk/lib/_internal/compiler/implementation/compiler.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js;
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
@@ skipping 375 matching lines @@
 
   /**
    * URI of the main source map if the compiler is generating source
    * maps.
    */
   final Uri sourceMapUri;
 
   /// Emit terse diagnostics without howToFix.
   final bool terseDiagnostics;
 
-  /// If `true`, warnings and hints not from user code are not reported.
-  final bool hidePackageWarnings;
+  /// If `true`, warnings and hints not from user code are reported.
+  final bool showPackageWarnings;
 
   /// `true` if the last diagnostic was filtered, in which case the
   /// accompanying info message should be filtered as well.
   bool lastDiagnosticWasFiltered = false;
 
+  /// Map containing information about the warnings and hints that have been
+  /// suppressed for each library.
+  Map<Uri, SuppressionInfo> suppressedWarnings = <Uri, SuppressionInfo>{};
+
   final api.CompilerOutputProvider outputProvider;
 
   bool disableInlining = false;
 
   List<Uri> librariesToAnalyzeWhenRun;
 
   final Tracer tracer;
 
   CompilerTask measuredTask;
   Element _currentElement;
@@ skipping 202 matching lines @@
             bool generateSourceMap: true,
             this.analyzeAllFlag: false,
             bool analyzeOnly: false,
             bool analyzeSignaturesOnly: false,
             this.preserveComments: false,
             this.verbose: false,
             this.sourceMapUri: null,
             this.buildId: UNDETERMINED_BUILD_ID,
             this.terseDiagnostics: false,
             this.dumpInfo: false,
-            this.hidePackageWarnings: false,
+            this.showPackageWarnings: false,
             outputProvider,
             List<String> strips: const []})
       : this.analyzeOnly = analyzeOnly || analyzeSignaturesOnly,
         this.analyzeSignaturesOnly = analyzeSignaturesOnly,
         this.outputProvider = (outputProvider == null)
             ? NullSink.outputProvider
             : outputProvider {
     world = new World(this);
 
     closureMapping.ClosureNamer closureNamer;
@@ skipping 451 matching lines @@
           (_, lib) => fullyEnqueueLibrary(lib, enqueuer.resolution));
     }
     // Elements required by enqueueHelpers are global dependencies
     // that are not pulled in by a particular element.
     backend.enqueueHelpers(enqueuer.resolution, globalDependencies);
     resolveLibraryMetadata();
     processQueue(enqueuer.resolution, main);
     enqueuer.resolution.logSummary(log);
 
     if (compilationFailed) return;
+    if (!showPackageWarnings) {
+      suppressedWarnings.forEach((Uri uri, SuppressionInfo info) {
+        MessageKind kind = MessageKind.HIDDEN_WARNINGS_HINTS;
+        if (info.warnings == 0) {
+          kind = MessageKind.HIDDEN_HINTS;
+        } else if (info.hints == 0) {
+          kind = MessageKind.HIDDEN_WARNINGS;
+        }
+        reportDiagnostic(null,
+            kind.message({'warnings': info.warnings,
+                          'hints': info.hints,
+                          'uri': uri},
+                         terseDiagnostics),
+            api.Diagnostic.HINT);
+      });
+    }
     if (analyzeOnly) {
       if (!analyzeAll) {
         // No point in reporting unused code when [analyzeAll] is true: all
         // code is artificially used.
         reportUnusedCode();
       }
       return;
     }
     assert(main != null);
     phase = PHASE_DONE_RESOLVING;
@@ skipping 272 matching lines @@
   void reportInternalError(Spannable node, MessageKind messageKind,
                            [Map arguments = const {}]) {
     reportDiagnosticInternal(
         node, messageKind, arguments, api.Diagnostic.CRASH);
   }
 
   void reportDiagnosticInternal(Spannable node,
                                 MessageKind messageKind,
                                 Map arguments,
                                 api.Diagnostic kind) {
-    if (hidePackageWarnings) {
+    if (!showPackageWarnings) {
       switch (kind) {
       case api.Diagnostic.WARNING:
       case api.Diagnostic.HINT:
-        if (!inUserCode(elementFromSpannable(node))) {
+        Element element = elementFromSpannable(node);
+        if (!inUserCode(element)) {
+          Uri uri = getCanonicalUri(element);
+          SuppressionInfo info =
+              suppressedWarnings.putIfAbsent(uri, () => new SuppressionInfo());
+          if (kind == api.Diagnostic.WARNING) {
+            info.warnings++;
+          } else {
+            info.hints++;
+          }
           lastDiagnosticWasFiltered = true;
           return;
         }
         break;
       case api.Diagnostic.INFO:
         if (lastDiagnosticWasFiltered) {
           return;
         }
         break;
       }
@@ skipping 179 matching lines @@
   /// If an entrypoint URI uses the 'package' scheme then every library from
   /// that same package is considered to be in user code. For instance, if
   /// an entry point URI is 'package:foo/bar.dart' then every library whose
   /// canonical URI starts with 'package:foo/' is in user code.
   ///
   /// If an entrypoint URI uses another scheme than 'package' then every library
   /// with that scheme is in user code. For instance, an entry point URI is
   /// 'file:///foo.dart' then every library whose canonical URI scheme is
   /// 'file' is in user code.
   bool inUserCode(Element element) {
-    if (element == null) return false;
-    Uri libraryUri = element.getLibrary().canonicalUri;
     List<Uri> entrypoints = <Uri>[];
     if (mainApp != null) {
       entrypoints.add(mainApp.canonicalUri);
     }
     if (librariesToAnalyzeWhenRun != null) {
       entrypoints.addAll(librariesToAnalyzeWhenRun);
     }
+    if (entrypoints.isEmpty) {
+      // Assume in user code since [mainApp] has not been set yet.
+      return true;
+    }
+    if (element == null) return false;
+    Uri libraryUri = element.getLibrary().canonicalUri;
     if (libraryUri.scheme == 'package') {
       for (Uri uri in entrypoints) {
         if (uri.scheme != 'package') continue;
         int slashPos = libraryUri.path.indexOf('/');
         if (slashPos != -1) {
           String packageName = libraryUri.path.substring(0, slashPos + 1);
           if (uri.path.startsWith(packageName)) {
             return true;
           }
         } else {
           if (libraryUri.path == uri.path) {
             return true;
           }
         }
       }
     } else {
       for (Uri uri in entrypoints) {
         if (libraryUri.scheme == uri.scheme) return true;
       }
     }
     return false;
   }
 
+  /// Return a canonical URI for the source of [element].
+  ///
+  /// For a package library with canonical URI 'package:foo/bar/baz.dart' the
+  /// return URI is 'package:foo'. For non-package libraries the returned URI is
+  /// the canonical URI of the library itself.
+  Uri getCanonicalUri(Element element) {
+    if (element == null) return null;
+    Uri libraryUri = element.getLibrary().canonicalUri;
+    if (libraryUri.scheme == 'package') {
+      int slashPos = libraryUri.path.indexOf('/');
+      if (slashPos != -1) {
+        String packageName = libraryUri.path.substring(0, slashPos);
+        return new Uri(scheme: 'package', path: packageName);
+      }
+    }
+    return libraryUri;
+  }
+
 }
 
 class CompilerTask {
   final Compiler compiler;
   final Stopwatch watch;
 
   CompilerTask(Compiler compiler)
       : this.compiler = compiler,
         watch = (compiler.verbose) ? new Stopwatch() : null;
 
@@ skipping 118 matching lines @@
 
   void close() {}
 
   toString() => name;
 
   /// Convenience method for getting an [api.CompilerOutputProvider].
   static NullSink outputProvider(String name, String extension) {
     return new NullSink('$name.$extension');
   }
 }
+
+/// Information about suppressed warnings and hints for a given library.
+class SuppressionInfo {
+  int warnings = 0;
+  int hints = 0;
+}